It is unlawful to drain large volumes of water directly into the sewer and thereby cause surcharging of sewer lines. Swimming pools, public or private, shall not be connected to the sewer. Discharge of swimming pools into the sewer shall be allowed; provided, that the city is authorized to enter into agreement with owners of private and public swimming pools to provide for off-hour discharge of pool waters into city lines, where this is done under the supervision of the public works director and at such hours as the director may direct. Any such connection shall include a keyed valve to be opened only by the public works director or the director’s authorized representative. (Ord. 1634 § 1, 1996).